1. Field of the Invention
This invention relates to power tong assemblies used to grip drill pipe and other similar tubular members. More particularly, this invention relates an apparatus that can safely and effectively position a power tong assembly for engagement with tubular members.
2. Prior Art
Pipe tongs are often employed in the oil and gas industry to break apart or tighten together threaded tubular member connections. It is generally required that one set of pipe tongs grip and rotate one section of tubular member and one set of pipe tongs grip and hold stationary the other section of tubular member. Modern drilling operations usually employed powered pipe tongs, or power tongs. The first tong rotating the tubular member is referred to as the power tong, while the second tong holding the tubular member stationary is referred to as the back-up power tong. Suitable power tongs can include devices such as those disclosed in U.S. Pat. Nos., 5,671,961, 5,819,604, and 5,702,139 to Buck, which are incorporated herein by reference.
Presently, when power tong assemblies are placed into operation, they are suspended from cables as shown in FIG. 1. When lengths of tubular members are joined ("made-up") or disconnected ("broken"), a power tong 3 engages and grips a first tubular member 1 and a back-up power tong 4 engages and grips a lower tubular member 2. As power tong 3 grips and rotates upper tubular member 1 and back-up power tong 4 grips and holds stationary lower tubular member 2, upper tubular member 1 is either forced toward or away from lower tubular member 2 by action of the corresponding threads on tubular members 1, 2.
Often when running larger diameter tubulars, a power tong may be used without a back-up power tong. In such an operation, the power tong is suspended from a cable similar to that shown in FIG. 1. To prevent rotation of the power tong and to hold the power tong in position horizontally, one or more cables may be anchored onto the drilling rig itself and connect to the power tong. This type of operation can be dangerous should one of the supporting cable break during operation.
Power tongs are bulky and heavy tools, with larger tongs weighing as much as 2,300 pounds and even smaller tongs weighing 1,500 to 1,800 pounds. Because of the size and bulk, three or more operators may be needed to position the power tong so that the tongs can grip the tubular members. Because the tongs are suspended from cables, they may swing freely and could potentially strike the nearby operators if not properly handled. What is needed in the art is a device that can reduce the number of operators required to effectively handle the power tong, while at the same time addressing the safety concerns associated with suspending the power tong from cables.